[all-commits] [llvm/llvm-project] 82ef7e: [X86] combineVTRUNCSAT - attempt to recognise VTRU...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 82ef7e54d3e644a26a834b240f590287cf3ee352
      https://github.com/llvm/llvm-project/commit/82ef7e54d3e644a26a834b240f590287cf3ee352
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2026-03-08 (Sun, 08 Mar 2026)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/masked_packss.ll
    M llvm/test/CodeGen/X86/masked_packus.ll
    M llvm/test/CodeGen/X86/packss.ll
    M llvm/test/CodeGen/X86/packus.ll

  Log Message:
  -----------
  [X86] combineVTRUNCSAT - attempt to recognise VTRUNCS/US(CONCAT(X,Y)) -> PACKSS/US(X,Y) folds. (#178707)

If we're just concatenating subvectors together to perform a saturated
truncate, see if we can perform PACK on the subvectors directly instead
- 256-bit PACK will require a post-shuffle, but this will typically fold
away in later shuffle combining and its probably better than changing
vector widths with concats.

Reference patch based off poor codegen identified in #169995



To unsubscribe from these emails, change your notification settings at https://github.com/llvm/llvm-project/settings/notifications